1221112202221 has 2 divisors, whose sum is σ = 1221112202222. Its totient is φ = 1221112202220.

The previous prime is 1221112202207. The next prime is 1221112202227. The reversal of 1221112202221 is 1222022111221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 984321936900 + 236790265321 = 992130^2 + 486611^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221112202221 - 2²⁷ = 1220977984493 is a prime.

It is a super-2 number, since 2×1221112202221² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221112202227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610556101110 + 610556101111.

It is an arithmetic number, because the mean of its divisors is an integer number (610556101111).

Almost surely, 2^{1221112202221} is an apocalyptic number.

It is an amenable number.

1221112202221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221112202221 is an equidigital number, since it uses as much as digits as its factorization.

1221112202221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 1221112202221 its reverse (1222022111221), we get a palindrome (2443134313442).

The spelling of 1221112202221 in words is "one trillion, two hundred twenty-one billion, one hundred twelve million, two hundred two thousand, two hundred twenty-one".